Number of n-length words w over a 7-ary alphabet such that w is empty or a prefix z concatenated with letter a_i and i=1 or 0 < #(z,a_{i-1}) >= #(z,a_i), where #(z,a_i) counts the occurrences of the i-th letter in z.
A240613
Number of n-length words w over a 7-ary alphabet such that w is empty or a prefix z concatenated with letter a_i and i=1 or 0 < #(z,a_{i-1}) >= #(z,a_i), where #(z,a_i) counts the occurrences of the i-th letter in z.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =46a(6) =165a(7) =651a(8) =2770a(9) =12601a(10) =60686a(11) =305658a(12) =1595454a(13) =8547278a(14) =46685641a(15) =258530476a(16) =1446098060a(17) =8148181066a(18) =46165702543a(19) =262699285827
External references
- oeis: A240613